In this work, ammonium sulfide ((NH4)2S) solution was used to passivated the surfaces of InP substrate. The optical
properties were measured by PL (Photoluminescence) measurement, the luminescence intensity increased about 7 times
when the passivated time was 15 min. The reasons of enhanced luminescence were also discussed. After passivating, the surface morphology and electrical properties were analyzed by atomic force microscopy (AFM) and Hall effect, respectively